Fuel cell system

Abstract

A fuel cell generates electric power by the electrochemical reaction of hydrogen and the oxygen in air. After the hydrogen discharged without being consumed by an anode is burned in a burner, it is discharged out of a fuel cell system. Therefore, the fuel cell system has a cathode switch valve in the middle of the cathode line, and when the fuel cell system stops, non-saturated air of a compressor bypasses the fuel cell, and supplies the air to the catalytic burner. Although the cathode exhaust gas of saturated water vapor is circulating to the catalytic burner at the time of regular operation of the fuel cell, the non-saturated air which bypasses the fuel cell and is supplied can replace the inside of the catalytic burner with dry air. Therefore, the amount of water vapor in the catalytic burner is decreased at the time of a stop, and the catalyst is quickly activated at the time of re-starting.

Description

BACKGROUND OF THE INVENTION [0001] The fuel cell system currently described by JP2002-343391A is equipped with a catalytic burner which burns hydrogen discharged from a Polymer Electrolyte Fuel Cell [PEFC] in order to prevent discharge of hydrogen to the atmosphere. While the PEFC using a solid high polymer electrolyte has a low temperature of operation and handling is easy, the high polymer electrolyte film has the characteristic of not fully demonstrating hydrogen ion conductivity, if not fully humidified. The solid high polymer type fuel cell has a stratified structure that alternately piles up a separator and a resin film with hydrogen conductivity. The separator forms the hydrogen channel in one side, and forms the air channel in an opposite side. The fuel cell system is comprised of a hydrogen supply device with which a fuel cell system supplies hydrogen as fuel gas, a compressor that supplies air as oxidizer gas, and a fuel cell stack which has an anode and a cathode. However...

AI Technical Summary

Benefits of technology

[0005] Since the water vapor in the catalytic burner can be transposed to cathode gas and the water vapor in the catalytic burner can be decreased, a catalyst carries out activity quickly at the time of starting of the fuel cell. Moreover, since it becomes unnecessary to provide the blower that takes in air from the exterior to the catalytic burner, the fuel cell system becomes simple in composition.

Problems solved by technology

However, in the fuel cell system mentioned above, in the case of rainy weather, or in high humidity, since water vapor is contained in the air which is inhaled by the blower, a catalytic burner does not function properly.

Furthermore, when a catalytic burner is filled with high humidity air, when a fuel cell stops and temperature falls, the water vapor in a catalytic burner may saturate, and moisture may condense on the catalyst surface.

When moisture adheres to the catalyst surface, it becomes impossible for the catalytic burner to burn hydrogen.

Moreover, because a car has space restrictions, the system which needs both the compressors which supply air to a fuel cell and the blower for burners is not desirable.

Images